While clinical depression cannot evolve or develop into bipolar disorder, a person who was previously diagnosed with depression may discover that they actually have a type of bipolar disorder. Depressive episodes are common at the onset of bipolar disorder, as shown in retrospective and prospective studies. The proportion of people with an episode of depressive index varies between studies, but is consistently higher than 50% (range 50 to 80%). Family data suggest that baseline polarity is possibly an inherited trait and may identify separate genetic subtypes of bipolar disorder (BD) (.
Recent studies have questioned current diagnostic systems that divide mood disorders into separate categories of bipolar disorders and depressive disorders. The current classification of mood disorders runs counter to Kraepelin's unitary view of manic-depressive insanity (illness). We present the main findings of recent studies that support a continuity between bipolar disorders (mainly bipolar II disorder) and major depressive disorder. Characteristics that support a continuity between bipolar II disorder and major depressive disorder are currently mixed depressive states (mixed depression) and dysphoric hypomania (mixed) (symptoms of opposite polarity in the same episode do not support the division of mood disorders); family history (depression major) is the most common mood disorder in relatives of bipolar probands); lack of points of rarity between depressive syndromes of bipolar II disorder and major depressive disorder; major depressive disorder with bipolar characteristics such as mixed depressive states, age at young onset, atypical characteristics, bipolar family history, irritability, accelerated thoughts and psychomotor agitation; a high proportion of major depressive disorders that change to bipolar disorders during long-term follow-up; a high proportion of major depressive disorders with a history of manic and hypomanic symptoms; present in episodes of depressive disorder; recurrent course of major depressive disorder; and depressive symptoms much more frequent than manic and hypomanic symptoms in the course of bipolar disorders.
Bipolar disorder (sometimes called manic depression) is different. If you have it, you have extreme mood swings. You experience periods of depression (similar to MDDs). But you also have periods of great ups and downs.
This diagnosis is given when a patient has had at least one depressive episode and a period of elevated mood called hypomania. The possible post hoc fallacy, assuming that an antidepressant has been effective, must be balanced with the presumed natural duration of a depressive episode, which in prebipolar depression can be quite short with a sharp shift. It's also possible to have a type of bipolar disorder in which you experience manic and depressive symptoms at the same time. The Table lists the risk factors that should be evaluated that would support a diagnosis of BDI depression as opposed to unipolar depression.
In another long-term prospective cohort of patients with major depression followed for an average of 17.5 years, the rate of new onset of mania was 7.5% and hypomania was 12.2%. If previous psychiatric history reveals previous episodes of mania, mania with mixed characteristics, or significant hypomania, the current major depressive episode should be treated as BDI depression and antidepressant medications should be avoided. This is diagnosed when a patient has had at least one manic episode, regardless of whether or not there has been a depressive episode. The essential feature of major depressive disorder is a two-week period during which there is depression most of the day, almost every day, or loss of interest or pleasure in almost all activities.
Researchers suggest that mixed characteristics may fit into a continuum ranging from pure mania to pure depression. Some studies suggest that there is also a difference in the manifestation of early depression depending on family history. This was replaced by a new specifier for bipolar disorder and unipolar depression, called “mixed characteristics”. Since the choice of treatments for a primary bipolar disorder (major depressive episode) versus an episode of unipolar major depression is significantly different, this information will help guide physicians on how to proceed.
Of the people who have an episode of major depression, a certain proportion may actually be suffering from bipolar depression. Receiving a misdiagnosis can delay a person's recovery, as depression and bipolar disorder are usually treated with different medications. Existing literature supports the distinction between depression, which is probably a manifestation of bipolar disorder, and depressive disorder. Children and teens may have different major depressive episodes, manic or hypomanic episodes, but the pattern may vary from adults with bipolar disorder.